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Interactive Algorithm Visualizer

Write Code. Watch It Think.

A full-screen IDE where you write any algorithm, run it against real inputs, and watch a step-by-step animated breakdown of exactly how it works - arrays shifting, hash maps filling, pointers advancing, trees branching. 14 pattern detectors. 5 languages. Zero setup.

Browse Problem Library
14
Detected Patterns
5
Languages
∞
Custom Algorithms
0
Setup Required
What the Playground looks like
Algorithm Playground
TypeScriptJavaScriptPython
Editor● Array & Hashing
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function twoSum(nums, target) {
const map = new Map();
for (let i = 0; i < nums.length
const comp = target - nums[i]
if (map.has(comp)) {
return [map.get(comp), i];
}
map.set(nums[i], i);
}
}
▶ Run
⚡ Visualize
● Output: [0, 1] (2ms)
Visualization
Step 3 / 8
⏮⏪⏩⏭
nums = [2, 7, 11, 15]
2[0]
7[1]
11[2]
15[3]
↑ i=0
HashMap (map)
2→ 0
Current Step
Checking i=0: comp = 9 - 2 = 7
map.has(7)? → false → store map[2]=0
Active step highlighted in editor
Real output verified
Live data structure render
Simple 3-Step Flow

How It Works

01
Write or Paste Code
Open the full-screen playground and paste your algorithm - or pick from a starter template. Supports 5 languages.
02
Run with Test Input
Provide your input values (e.g. nums = [2,7,11,15], target = 9), hit Run, and verify your code produces the right output.
03
Visualize & Explore
Select your algorithm pattern, click Visualize, then step through each iteration watching arrays, maps, and pointers update in real time.
Everything you need

Packed with features

Live Code Execution
Run JavaScript & TypeScript code directly in the browser with real output, error messages, and execution time.
Step-by-Step Highlights
As you navigate each visualization step, the corresponding lines in your editor glow - exactly like a real debugger.
14 Pattern Visualizers
Two Pointers, Sliding Window, DP, BFS/DFS, Backtracking, Stack, Linked List - each rendered with bespoke animated frames.
5 Languages Supported
TypeScript, JavaScript, Python, Java, and C++ - starter templates included for every language.
Complexity Analysis
Pattern detection automatically surfaces time and space complexity for your algorithm as you type.
Resizable Split View
Drag the divider between the code panel and visualization panel to get exactly the layout you need.
Infinite Loop Guard
A built-in 100k-iteration circuit breaker prevents runaway code from locking your browser tab.
No Setup Required
Fully browser-based - no installs needed. Open the playground and start visualizing in seconds. Works on any modern browser.
Real-time line highlights

See exactly which line the algorithm is executing

As you step forward or backward through the visualization, the corresponding lines in your code editor light up in real time - no guessing which part of your loop is running.

Highlight overlay synced with visualization steps
Forward and backward navigation
Auto-scroll to keep active line visible
Works with any algorithm you write
Editor - line highlight demo
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function maxSubarray(nums) {
let maxSum = nums[0];
let curr = nums[0];
for (let i = 1; i < nums.length
curr = Math.max(nums[i],
maxSum = Math.max(maxSum, curr)
}
return maxSum;
}
● Step 3 / 7curr = max(−2, 3) = 3Kadane's Algorithm
14 Supported Visualization Patterns
Two Pointers
Sliding Window
Binary Search
Array & Hashing
Stack
Dynamic Programming
Trees
Linked List
Graphs / BFS
Backtracking
Kadane's Algorithm
Greedy
Prefix Sum
Matrix

Ready to visualize your algorithm?

Open the full-screen playground, paste your code, run it, and watch every iteration unfold visually - no setup, no installs.

Browse Problem Library DSA Overview